I was gonna downvote based on this but then I checked where it was posted

Measured, it would be CoD MW2 (the original) with over 30 days, played across 2 years

Unmeasured, easily Championship Manager (later changed to Football Manager). In one year I’d over 40 days but I was still in school back then. If I added up all the years together it would be an unbelievable number. I played it pretty much daily from about 1997 until 2004. Then picked up Football Manager from around 2005 until 2008 (I stopped as online FPS took over)

Latest version I have played is FM2022 but barely played the more recent ones in comparison to the older versions. I still play the old one from time to time, thanks to Nicks Patcher

Sugma balls!!

Haha, gottem